Compound electrical switch



July 1 7, 1962 K. PREISSLER ETAL COMPOUND ELECTRICAL SWITCH Filed June 23, 1960 2 Sheets-Sheet 1 Jive/215cm July 17, 1962 K. PREISSLER ET AL COMPOUND ELECTRICAL SWITCH 2 Sheets-Sheet 2 Filed June 28, 1960 wr/ ein/er fl-fr/eal 14/421 Jnrenfors Uniteid tates. Patent @ffice ass-4.80s Patented 51.11.3717, 1962 3,044,806 CUMPQUND ELEQTRICAL SWITQH Karl lreissler and Gottfried Alsch, Vienna, Austria, assignors to Hubert Laurens Naimer, Vienna, Austria Filed June 28, 1960, Ser. No. 39,350 Claims priority, application Austria July 10, 1959 3 Claims. (ill. 2372li) ln-the large-scale manufacture of electrical devices in several series of different power, voltage or current rating, which differ mainly in their dimensions, it is frequently desirable for standardization and efficient rational production to provide for types of different size and rating a maximum number of parts which are identical for all types of one or even several series. For similar reasons the tendency has been to increase the rating of a unit or facilitate the performance of special functions thereof by assembling the equipment from prefabricated identical units. For instance, it is usual to assemble cam-operated switches which must perform complicated switching programs from a number of identical units, the number of which varies depending on requirements; these units are aligned on a common operating shaft. In this case the units forming the switch must be connected to form an assembly. This is effected in most cases by bolts, which extend parallel to the axis of the units. To continue the consideration of this example, it is sometimes necessary to provide these switches on one side with various attachments, designed to correspond to specific conditions of installation. For instance it may sometimes be necessary to provide a complete cam-operated switch with special means for mountin-g'it on a switchboard. For this purpose a special adapter is in terpos-ed between the switch body and the switchboard.

it may also "be required to combine the switch with a lock, a signal lamp or with an auxiliary switch for the control of signalling circuits. In all these cases it is desirable to have between these uni-ts a joint which is of universal utility, can be rapidly put together and can be quickly and simply separated in the case of later changes of the assembly, and which can be used with all possible variations in the assembly of the several units.

in electrical equipment which comprises movable parts, particularly parts which are arranged for a sudden movement, such as cam-operated switches or contactors, reaction forces which produce impacts may be caused in operation by spring-loaded parts returning suddenly to their rest positions, suddenly attracted armatures, or the like. These forces tend to loosen the elements which hold the several parts together. This has led to the generally accepted rule of construction that the parts which serve I for holding the equipment together, such as tie rods, fastening means and the like, should be designed as screws or rivets, i.e. as positive-locking elements. For a quick assembly, however, it would be desirable .to use elements which can be quickly made and hold only by friction.

it has already been proposed to provide such a joint for connecting units of electrical equipment composed of a plurality of prefabricated units and having moving internal parts, particularly for compound cam-operated switches by providing at least two units on their adjoining boundary faces, i.e. on their confronting end surfaces in the assembled equipment, with holding means which combine in a manner known per se to form a bayonet joint. I It is surprising that this enables a permanently safe, though only frictionally held, connection of parts even in electrical equipment in which impace forces are set up. It is of special advantage to make the cooperating holding elements of the bayonet joint or at least those of one half of the joint from a non-metallic thermoplastic superpolyamide-type plastic, because it has been found that the deformation and friction characteristics of these materials are highly desirable for the present purposes. This has also the advantage that the part which forms the bayonet joint can be produced by injection moulding in a particularly economical manner.

The use of bayonet joints in electric engineering is not new and is conventional, e.g. in cable couplings or plug connections. It is new, however, in its application to electrical equipment the component parts of which are subjected to substantial impact forces, particularly to switches, contactors, brake-lifting magnets and the like.

if this joint is so designed that only female parts of the bayonet connection are provided on the boundary surface of one unit and only male parts of the bayonet connection are provided on the coacting boundary surface of the adjacent unit, two units can be connected only in a predetermined relative position. If, for example, a multiple switch is imagined which consists of individual cam-operated switches having each a cup-shaped first housing part and a cover shaped second housing part, these individual switches can only be assembled so that the cup opening of all housings is on one and the same side. This is a result of the assumption that, in this example, the bottom of the cup is always provided with, e.g., the female parts and the cup cover, which complements the cup to form the complete individual switch housing, is always formed with the male parts. For this reason it will not be possible to assemble a multiple switch in which two individual switches contact or face each other at their cup bottoms or their cup covers because the female parts of one bottom cannot be connected to other female parts but only to male parts and these are formed on the other housing part.

Whereas this restriciton regarding the assembly may be without significance in individual switches, it assumes a greater and even very great significance if the switch is to be adapted to a special application by the provision of accessories. Such accessories are auxiliary switches, adapters, e.g., for signal lamps, locking devices, counters and the like, and form units which should also be connected by a bayonet connection to the switch proper. For these special cases it is often desirable to depart from the pregiven arrangement of the individual parts as is required by the above-mentioned design of the bayonet lock in order of increase the number of variations in which the prefabricated parts can be combined. 7

The present invention accomplishes this object and resides in a joint of the kind described hereinbefore in which each of the two boundary faces of the units to be connected carries at least one female part as well as one male part of the bayonet connection and in which these female and male parts are so dimensioned as to interengage with each other. If this special design of a bayonet connection is applied to parts of electrical equipment having a central axis, the female and male parts will preferably be arranged with radial symmetry relative to this axis.

For a better understanding of the invention, reference will be made to the accompanying drawing, inwhich:

FIG. 1 is a sectional view showing the arrangement of the female and male parts;

FIG. 2 is an end view of a switch component, having a central axis, of a cam-operated switch mechanism;

FIGS. 3 and 4 are sectional views taken on lines IIIIII and lV-IV, respectively, of FIG. 2;

FIG. 5 is a plan view of a locking member according to the invention;

FIG. 6 is a cross-sectional view taken along line VI-VI of FIG. 5; and 1 FIG. 7 is a similar view taken along line VII-VII of FIG. 5.

spaasoe In FIG. 1, 1 denotes the first switch component and 2 the second component of the electrical equipment. These components are connected by means of a bayonet connection at the interface 3. It is seen that each of the components 1 and 2 has a female part or recess 4- as well as a male part or lug 5 and that where a female part 4- is disposed at one end face in of one component unit 1 a male part is disposed at the confronting end face of the other component unit 2 and vice versa and that the female and male parts of both units 1 and 2 are equally spaced by the distance a; the female and male parts of each unit are so dimensioned as to interengage with each other. This enables the two units 1 and 2 to be connected to each other not only in the illustrated position of the units 1 and 2 but also in a position in which unit 2 has been turned so that its end face 2a is now in position 3. If unit 2 is also turned about its axis x-x by 180, a female part 4 of one unit 1 or 2 will again be juxtaposed with a male part 5 of the respective other part so that it is actually possible to connect the units 1 and 2 to each other not only in the illustrated position but also in a position in which the surfaces in and 2a face each other, as has been explained more fully hereinbeforc.

This principle can be applied to a switch housing such as shown in FIG. 2 with the following results:

The recesses 4 and the lugs 5 are alternatingly arranged around the periphery of the component and are radially symmetrically arranged with respect to the center 0. Accodring to the principle apparent from FIG. 1, two components provided in this way with corresponding bayonet elements can be assembled as has already been described it the rear side of the part of construction shown in FIG. 2 is also provided with bayonet connection elements in the manner explained with reference to FIG. 1.

It is also apparent from FIG. 1 that the two units 1 and 2 must perform a displacement in the direction A to effect the locking. This movement has the dimension b. This consideration can find logical application in FIG. 2 with the difference that the movement A is a rotation about 0. FIG. 1 could be imagined to be an enlarged sectional view, taken on line I-I of FIG. 2 and developed into a plane. It is thus apparent that the cavities 6 of FIG. 1 correspond in FIG. 2 to peripherally open recesses or to recesses which can easily be made peripherally open, e.g., if the bayonet parts 4, 5, FIG. 2, are disposed at the periphery of unit 2, as is the case for FIG. 2.

These peripherally open recesses can be conveniently used to accommodate locking members which are radially inserted into these recesses in the direction toward the center of the part of construction 2 and thus prevent a reverse rotation of the interlocked parts to the release position. These locking members must be appropriately protected against falling out of the recesses in which they are disposed.

In FIGS. -7 one such locking member 10 is shown. It consists of a member having an external shape conforming to the shape of the recess and constituting, as a rule, a sector of a ring. This member has cuts 11, 12 and 13 to form a tongue 14, which tends to spring outwardly and thus to anchor like a rib in a mating enlargement of the above-mentioned recess 6, which has for this purpose an undercut or wall recess (16in FIG. 1) provided in its side walls. By the insertion of a screwdriver into the recess 17 of the tongue 14 the tongue can be removed from the recess 16 so that the insert or locking member 10 can be removed from the recess 6. Like components 1 and 2 this insert 10 consists of a synthetic thermoplastic of adequate strength and elasticity.

:In the illustrative embodiment shown in FIG. 4 it is assumed that there are four interengaging pairs of females and males. It is apparent, however, that this is not essential because any other number of pairs may also be provided. One of the prefabricated units to be assembled may have a larger number of bayonet parts than the other units. It is only essential that at least one mating part is provided on the other part and that the part having fewer bayonet connection elements is formed with cavities into which the unutilized bayonet connection elements of the other parts can extend. It is not essential, of course, that parts 1 and 2 are in snug engagement along a plane, as is shown in FIG. 1. Parts 1 and 2 or at least one of them may be so designed that there is a clearance between parts 1 and 2. Nor is it essential to lock the parts relative to each other by the inserts shown in FIGS. 5-7.

We claim:

1. A compound electrical switch comprising at least two component units having confronting end surfaces, each of said surfaces being provided with a pair of spacedapart connecting elements forming a bayonet coupling with a pair of spaced-apart complementary connecting elements on the respectively opposite surface, thereby securing said units in a predetermined aligned position; one of said units being provided with a recess open at its end surface and at its periphery, said one unit also having a projection partly overlying said recess and constituting one of said connecting elements, the other of said units being provided with a lug projecting from its end surface and constituting another of said connecting elements complementarily therewith, said lug being insertable into said recess and engageable with said projection upon a relative displacement of said confronting end surfaces, said lug forming with the walls of said recess a channel opening at the periphery of said one of said units; and a resilient locking member inserted into said channel and bearing upon said lug and a wall of said recess opposite said lug for preventing a reverse displacement of said units, said locking member having a wedge portion with tapered flanks engaging said end surfaces and bearing upon said units in a sense urging them away from one another in a direction transverse to said end surfaces against the retaining force between said projection and said lug.

2. A compound electrical switch comprising at least two generally disk-shaped component units having confronting end surfaces, each of said surfaces being provided with a pair of diametrically spaced peripheral connecting elements forming a bayonet coupling with a pair of diametrically spaced peripheral complementary connecting elements on the respectively opposite surface, thereby securing said units in substantially axial alignment; one of said units being provided wtih a recess open at its end surface and at its periphery, said one unit also having a projection partly overlying said recess and constituting one of said connecting elements, the other of said units being provided with a lug projecting from its end surface and constituting another of said connecting elements complementarily therewith, said lug being insertable into said recess and engageable with said projection upon a relative angular displacement of said units, said lug forming with the walls of said recess a channel opening at the periphery of said one of said units; and a resilient locking member inserted into said channel and bearing upon said lug and a wall of said recess opposite said lug for preventing a reverse displacement of said units; said locking member having a wedge portion with tapered flanks engaging said end surfaces and bearing upon said units in a sense urging them away from one another in a direction transverse to said end surfaces against the retaining force between said projection and said lug.

3. A compound electrical switch comprising a plurality of stacked component units each having a pair of generally parallel end surfaces confronting respective end surfaces of adjacent units, one of said end surfaces of one unit being provided with a pair of spaced-apart connecting elements forming a bayonet coupling with a pair of spaced-apart complementary connecting elements on the juxtaposed surface of an adjacent unit, thereby securing said one unit to said adjacent unit in a predetermined aligned position; said one unit being provided with a recess at its end surface confronting said juxtaposed surface and at its periphery, said one unit further having a projection partly overlying said recess and constituting one of said connecting elements, said adjacent unit being provided with a lug projecting from said juxtaposed surface and constituting another one of said connecting elements complementarily therewith, said lug being insertable into said recess and engageable with said projection upon a relative displacement of said one unit and said adjacent unit, said lug forming with the walls of said recess a channel opening at said periphery of said one unit; and a resilient locking member inserted into said channel and bearing upon said lug and wall of said recess oppo site said lug for preventing a reverse relative displacement of said units, said locking member having a wedge portion with tapered flanks engaging said end surfaces and bearing upon said one unit and said adjacent unit in a sense urging them away from one another in a direction transverse to said end surfaces against the retaining force between said projection and said lug.

References Cited in the file of this patent UNITED STATES PATENTS Bachem Jan. 12, 1892 

